By this theorem, we obtain an explicit presentation of the right factor of order \(r\)  of \(L-\lambda _0\)  and \(M-\mu _0\)  that can be effectively computed. Hence an explicit description of the fiber \(\mathcal {F}_{P_0}\)  of the rank \(r\)  spectral sheave \(\mathcal {F}\)  in the terminology of [1]}, [2]}, where the operators are given in the ring of differential operators with coefficients in the formal power series ring \({\bf C}[[x]]\) .
